Southern West Virginia U.S. District Attorney R. Booth Goodwin II speaks to reporters Tuesday, Dec. 6, 2011, at the Robert C. Byrd federal courthouse in Charleston, W.Va. The U.S. Attorney's Office along with the Federal Bureau of Investigation and the Department of Labor's Office of Inspector General on Tuesday announced a non-prosecution agreement under which Alpha Natural Resources Inc. will make payments and safety investments totaling $209 million in connection with the April 5th, 2010 explosion at the Upper Big Branch mine that killed 29 coal miners and injured two others. (AP Photo/Brad Davis)

Photo: Brad Davis, AP

Southern West Virginia U.S. District Attorney R. Booth Goodwin II...

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United States District Attorney R. Booth Goodwin II, left, announces a $210 million agreement with Alpha Natural Resources Inc., in Charleston W.V., Tuesday Dec. 6, 2011, in connection with the criminal investigation of events surrounding the April 5, 2010 explosion at the Upper Big Branch mine that killed 29 men. It is the biggest settlement ever reached in a U.S. mining disaster. Assistant U.S. Attorney Steve Ruby, right, looks on. (AP Photo/The Charleston Gazette, Chris Dorst)

Photo: Chris Dorst, AP

United States District Attorney R. Booth Goodwin II, left,...

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WHITESVILLE, WV - APRIL 10: Mickie Green writes down the names of 29 fallen coal miners on a small memorial, on April 10, 2010 in Whitesville, West Virginia. According to reports December 6, 2011, Alpha Natural Resources, who bought Massey Energy after a fatal mining explosion in 2010, will pay close to a $210 million settlement for one of the worst mining distastes in U.S. history. (Photo by Mark Wilson/Getty Images)

In what officials say is the largest settlement in a government investigation of a mine disaster, Alpha Natural Resources agreed to pay $209 million in restitution and civil and criminal penalties for the role of its subsidiary, Massey Energy, in a 2010 mine explosion that killed 29 men in West Virginia.

That amount includes $46.5 million allocated to the families of the victims and those who were injured in the blast and includes terms that protect Alpha - but not individual Massey executives - from criminal prosecution, said Steven Ruby, an assistant U.S. attorney for the Southern District of West Virginia.

The announcement of the settlement came the same day that the Mine Safety and Health Administration imposed a $10.8 million fine - the largest in agency history - on the company as it wrapped up its investigation into the April 2010 explosion.

The federal agency said Massey and its subsidiary, which was operating the Upper Big Branch mine at the time of the blast, had been cited 369 times, including for improperly training miners, allowing hazardous levels of loose coal and coal dust to accumulate, and failing to comply with ventilation plans.

"The investigation found that the operator promoted and enforced a workplace culture that valued production over safety, including practices calculated to allow it to conduct mining operations in violation of the law," the agency said in a statement.

The investigation and the settlement, which was first reported by the Charleston Gazette, follows previous inquiries by federal officials from the Departments of Justice and Labor, as well as by an independent commission appointed by the former West Virginia governor.

Tuesday's announcement was made after federal investigators met with families of the victims in West Virginia.

"We believe this can change the way mining is done," said R. Booth Goodwin II, the U.S. attorney for the Southern District of West Virginia.

Goodwin said there had been no discussions between federal prosecutors and Massey about a settlement before Alpha purchased Massey in June.

In a statement Tuesday, Kevin Crutchfield, chief executive of Alpha Natural Resources, said that "the agreements we've reached represent the best path forward for everyone."

In the past, Massey had dismissed investigators' charges that its actions led directly to the disaster.

The settlement does not protect individual Massey managers, including former chief executive Don L. Blankenship, who have not been charged. In all, 18 executives refused to be interviewed by federal investigators, invoking their Fifth Amendment rights.

In addition to the $46.5 million payout to victims and families, the agreement includes $80 million to bolster safety and infrastructure in all underground mines owned by Alpha and Massey; $48 million to establish a mine health and safety foundation to be used to finance academic research on mine safety; and about $35 million in fines and fees that Massey owed to the Mine Safety and Health Administration, the branch of the Department of Labor that oversees the mining industry.